title: G-DNA: a twice-folded DNA structure adopted by single-stranded oligo(dG) and its implications for telomeres.
abstract: Our dimethyl sulfate modification experiments suggest that (dG)n stretches within single-stranded DNA fragments, which represent the simplest model for telomeric sequences, adopt a complex intrastrand structure other than a simple hairpin. We present a molecular model for the DNA structure that conforms to dimethyl sulfate methylation data. The principal element of this G-DNA structure is a quadruple helix formed by pairwise antiparallel segments of the twice-folded (dG)n stretch. This quadruple core has two wide and two narrow grooves connected by three loop-shaped segments. The strong stacking interactions of the neighboring guanine tetrads and the large number of hydrogen bonds formed can be the primary reasons that such structures are favored over a common hairpin for long (dG)n stretches. Such compact structures may be formed from (dG)n stretches of telomeric sequences.
authors.affiliation: N. D. Zelinsky Institute of Organic Chemistry, U.S.S.R. Academy of Sciences, Moscow.
authors.forename: I G
authors.initials: IG
authors.lastname: Panyutin
authors.forename: O I
authors.initials: OI
authors.lastname: Kovalsky
authors.forename: E I
authors.initials: EI
authors.lastname: Budowsky
authors.forename: R E
authors.initials: RE
authors.lastname: Dickerson
authors.forename: M E
authors.initials: ME
authors.lastname: Rikhirev
authors.forename: A A
authors.initials: AA
authors.lastname: Lipanov
mesh_terms: D002875:Chromosomes / Q000648:ultrastructure; D004247:DNA; D006860:Hydrogen Bonding; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides
chemical_list: D009838:Oligodeoxyribonucleotides; C033538:oligodeoxyguanylic acid; D004247:DNA